Roof mounted ventilator



Jan. 30, 1968 i H. R. LAMBIE ETAL 3,366,030

ROOF MOUNTED VENTILATOR Filed April 12, 1965 2 sheets-.sheet 1 INvENW-oaMMA Russe win( A4 ATTQRNEYS Jan. 30, 1968 H. R. I AMBlE ETAL l ROOF1MOUNTED VENTILATOR Filed April 12, 1965 2 Sheets-Sheet 2 United StatesPatent Ciiice liiidd Patented Jian. 310, i968 3,366,ll3tl FLGE MUUNTEDVENTILATE Howard Russell Lambie, Hayiing island, and Raymond A. F.Burtenslraw, Havant, England, assignors to Colt Ventilation and HeatingLimited, Surbiton, Engiand, a British company liiiled Apr. 12, i965,Ser. No. 447,186 Claims priority, application Great Britain, Apr. 13,1964, 15,226/64 2 Claims. (Cl. 98--43) This invention relates toventilators and is concerned with powered, upward discharge ventilatorsfor use without a weathering cowl. ln such a ventilator aself-weathering, non-return shutter assemblage is employed to close theexit from the extraction ian duct when the fan is not operating andthereby prevent weather entry and down draught, as well as conservingthe heat in the building.

According to the present invention there is provided a powered, upwarddischarge ventilator having a self weathering non-return shutterassemblage for closing the exit from the extraction fan duct of theventilator when the ventilator is not operating, the shutter assemblagebeing provided with a surrounding tubular windshield having an upper,open end and a lower end which is blocked or substantially whollyblocked by the shutter assemblage whereby, in use of the ventilator,entrainment of air into the air stream discharging from the shutterassemblage, through the tubular shield, from outside the shield, throughthe lower end of the shield, is wholly or substantially whollyprevented.

It will be understood that the shutter assemblage blocks the lower endof the tubular shield in the sense that it occupies the whole orsubstantially the 'whole ot the opening in its lower end whereby thelower end of the shield is open only to the air stream emerging throughthe non-return shutters and is closed when the non-return shutters areclosed.

Entrainment of air through the lower end of the windshield involves theunnecessary acceleration of extraneous air, with a consequent loss ofeiiciency of the ventilator. By substantially or wholly preventing suchentrainrnent, it has been found that the emciency of the ventilator maybe increased to a significant extent. Thus, by this means, a usefulcontribution may be made to increasing the capacity of the ventilator orto reducing the fan speed rwhilst maintaining the same rate ofextraction of air from the building and, in this way, reducing the noiselevel of the ventilator.

As will readily be appreciated, since the shutter assemblage blocks thelower end of the shield, the effect is to form a large open-toppedreceptacle for rain water when the extraction fan is not operating andthe nonreturn shutters are closed. At the expense of some entrainmenttherefore, openings must be left for the drainage of water from insidethe shield on to the roof around the outside of the non-return shutterassemblage.

The means provided to drain ott this water need not, however, be at theexpense of any significant entrainment of air into the windshield and.consequent loss of efciency provided that the openings are kept small.

According to a feature of the present invention, a guttering may beincorporated at the bottom of the tubular shield, the gutteringsurrounding the non-return shutters at a level below the plane of theshutter openings and communicating with one or more localised drainopenings for draining water to the outside of the windshield at rightangles.

The tubular shield may be of constant cross-sectional rea or it may besmoothly and upwardly convergent at least over an exit portion thereoftowards its upper end. Preferably however, the windshield is smoothlyand upwardly divergent at least over an exit portion thereof towards itsupper end, so as to reduce the velocity of discharge ot the air andthereby secure a further improvement in eciency of ex action for theventilator.

A specific embodiment of the present invention will now be described, byway of example, with reference to the accompanying drawings in which:

FlG. 1 is a side elevation of a powered upward discharge ventilatoraccording to the present invention partly broken away and partly incross-section to show certain details of construction, and

FIG. 2 is a plan view of the Ventilator shown in FIG. l.

Referring to the drawings, the ventilator comprises a self weatheringnon-return shutter assemblage generally indicated at 1li (see FG. 2).comprising a rectangular base plate 11 carrying a rectangular sectionedextract fan duct portion 12 which opens through the base plate 11 andextends upwardly therefrom. The self `weathering nonreturn shutters 13close this duct portion, the plane of the shutter openings correspondingwith that of the upper end of the duct portion 12 and lying above thelevel of the base plate 11. The base plate 11 has a surrounding,down-turned flange 1d at its outer periphery. A tubular `windshield 15,which is of corresponding rectangular cross-section to the base plate 1iat its lower end, is carried by the down-turned ilange 11's of the baseplate so as to extend upwardly above the level of the top of theshutters 13 when the shutters are in their fully open position (as shownchain dotted in FIG. l). The base plate 11 fully blocks the lower end ofthe tubular windshield. Small localised windows or drain openings 1S areprovided in the lower corners of each of the four walls of thewindshield at the level of the upper surface of the base plate 11.

The duct portion 12, a lower portion of the tubular wall of thewindshield 12 adjacent its lower end. and the base plate 11 togetherform a rectangular sectioned guttering 2@ surrounding the shutterassemblage at the bottom of the windshield 15 at a level below the levelof the plane of the shutter openings and this guttering collects waterentering the windsheld when the shutters are closed, the water drainingthrough the openings 18 to the outside of the windshield on to thesurrounding roof. The drain openings 1d are conveniently formed bycutouts extending from the lower edge of the windshield 15.

The windshield has a lower tubular portion of uniform cross-section andan upper, exit portion which is smoothly and upwardly divergent, thewalls of the exit portion being correspondingly r'lared outwardly. rlhevelocity of disharge of the air stream is accordingly slowed ia the exitportion. Alternatively, the windshield may be of constantcross-sectional area or again it may be smoothly and upwardly convergentover at least an exit portion thereof towards its upper end whereby thevelocity of discharge of the airstream is increased to carry it up- 3wardly well clear of the roof surface in special circumstances.

The self weathering shutter assemblage according to the present exampleis constructed as described in our co-pending application No. 413,715.The non-return shutters i3 are automatic in that they are opened by theforced draught of the fan and close under the action of gravity assistedby torsion bar springs when the fan is stopped. The windshield 1S actsto shelter the shutters l5 from movement by the wind both when they areopen and when they are closed.

Specifically, as may be seen by reference to FIG. 2, four hingedshutters 13 are employed. Each shutter is hinged on a hinge rod 13aradiating from the center of the non-return shutter assemblage. Aseparate hinge bracket 13b is provided to support the outer end of eachhinge rod i351, the bracket having an angled part overlying the shutteron the hinge rod, the angled part carry- Zing a rubber gromrnet plug 22which acts as a top lirniting the `opening of the shutter to an angleor" about .50 in the present example as shown in chain dotted outline inFIG. 1.

The shutter assemblage is hingeably mounted as 'at 24 on a pedestal basegenerally indicated at 25. The pedestal base houses the fan-motor unit2S of the ventilator. The pedestal base comprises an upper rectangularend plate 30 corresponding substantially in shape and dimensions withthe base plate l1 of the shutter assemblage and which tits within thedown turned flange 14 carrying the windshield l5, an intermediate ductportion 31 opening therethrough, the intermediate duct portion 3iCorresponding in cross-sectional shape and dimensions with the ductportion 12 of the shutter assemblage 1t) and forming the fan-motor unithousing, and a lower end plate 32 which is dashed (by means not shown)to the roof 33. The duct portion 31 of the pedestal base opens throughthe upper and lower end plates 30, 32 of the base and joins with theduct portion l2 of the shutter assemblage to form the extraction duct ofthe ventilator.

The shutter assemblage itl may be swung back on its hinge axis 2d toexpose the fan-motor unit 23 for servicing. Bolts 33 entered throughopen ended slots in the flange 14 and the lower edge of the windshieldcarry wing nuts 3d to secure the shutter assemblage lt) against openingwhen not desired.

The drain openings 18 lie parallel to the direction of the air streamemerging through the non-return shutters 15 when the ventilator isoperating. They are therefore, unfavourably disposed for entrainrnentthrough them of extraneous air. The openings 1S are nevertheless keptsmall whereby no significant loss due to entraiument of extraneous aircan take p-lace.

instead of forming the openings 18 in the tubular wall of the windshieldl5 they may be formed in the base plate lll. For example, the fourcorners of the base plate it may have drain openings, these openingscoinciding with openings in the upper end plate 30 O the pedestal base.The drain openings last described are kept small whereby no signiiicantloss occurs due to entrainment of extraneous air through the openings.

When the ventilator is operating, the shutters 113 float on the airstream discharged by the fan and the velocity of disharge of air throughthe windshield is suhcient to blow away rain and prevent it enteringthrough the shutter openings into the building.

When the fan is stopped the shutters close automatically. in theirclosed position each shutter 13 is inclined so as to drain water towardsand into the guttering 2li where it is collected and drained on to theroof through the drain openings i8. Gutters ll are also provided, aspart of the non-return shutter assemblage l), crossing the upper openend of the duct portion l2 to collect water draining ofi the shutters i3over the duct portion l2, into the guttering 2d.

The smoothly and upwardly divergent exit portion of the windshield l5acts on the discharging airstream to reduce the velocity of discharge ofthe air thereby reducing the kinetic energy dissipated in the airstrearnwithout iucurring substantial losses due to creating turbulence in theairstream and the pertorrnance of the ventilator is thus improved. Thiseffect is achieved despite the necessity of providing a gap between thelower end of the windshield and the duct portion l2, vthe upper end ofwhich deiines the exit of the extraction fan duct, to allow the drainageof water entering the upper end oi the windshield 15 downwardly outsidethe direction portion l?, between it and the windshield and into theglittering Zd. The shutters 13, since they are inclined with respect tothe airstrearn emerging from the extraction fan duct when open andparticularly when they are engaged against the shutter stops 22, act todeflect the airstream in part towards the inner surface of thewindshield whereby discharging air is assisted in bridging the drainageand attaching itself to the inner wall surface of the windshield. Theswirling motion imparted to the air in the fan impeller also assists inthis respect.

We claim:

A powered, direct upward discharge ventilator for a buildino comprisingan extracion fan duct having an upper, upwardly directed open end and alower open end, said extraction fan duct leading extracted air from thebuilding entering the lower open end of the duct from inside thebuilding outside the buiding through the upper upwardly directed openend of the duct, an extraction fan, first mounting means mounting saidextraction fan in said extraction tan duct, second mounting means, onsaid extraction fan duct for mounting the duct to the building,non-return shutters mounted on the upper upwardly directed open end ofthe extraction fan duct and arranged when open for the direct upwarddischarge of the extracted air through the upper upwardly directed openend of the extraction fan duct, and, when closed, to weather the upperupwardly directed open end of the extraction lan duct and to preventdowndraught and the loss of heat from inside the buildig, a tubularwindshield for said shutters, said windshield having a lower end thirdmounting means on said duct and outside said duct below the level of theupper upwardly directed open end of said duct and mounting said tubularwindshield to the extraction fan duct with the lower end of thewindshield below the level of the upper upwardly directed open end ofsaid extraction fan duct, the lower edge of the windshield surroundingthe upper upwardly directed open end of the extraction tan duct withclearance and deiining therewith an annular gap, the windshieldextending upwardly above the upper upwardly directed open end of theextraction fan duct to an upper upwardly directed open end through whichthe upper upwardiy directed open end of the extraction fan duct isexposed to direct weather entry, the improvement consisting in that thethird mounting means comprises a peripheral outwardly directed mount`ing llange on the exterior of extraction fan duct which ange at leastsubstantially wholly blocks said annular gap se as to prevent theentrainment of at least any substantial quantity of air from outside thebuilding through the lower end of the windshield into the airstreamdischarging through the upper, upwardly directed end of the extractionfan duct, said extraction fan duct cornprising a base portion having alower open end defining the lower open end of the duct, said baseportion having an outwardly directed ange at its upper end, and an openupper portion defining the upwardly directed open end of the duct, saidupper portion having an outwardly directed iiange at its lower endoverlying said first said flange at the upper end of the base portion ofthe duct, the outwardly directed Piange on the upper portion of the ductconstituting said peripheral mounting liange and carrying saidwindshield, and means is provided hingeably connecting said flanges.

2. A powered upward discharge ventilator as claimed in claim 1, whereinthe said windshield being smoothly and upwardly divergent at least overan exit portion thereof towards its upper end, so as to reduce thevelocity of discharge of the extracted air from the upper end of theWindshield.

References Cited UNITED STATES PATENTS 6 2,684,621 7/1954 Cook 98--116 X2,783,702 3/1957 ODay 98--111 X 3,012,495 12/ 1961 Miller 98-119 X3,181,451 5/1965 Hess 98-119 X FOREIGN PATENTS 129,416 8/ 1932 Germany.1 14,499 4/ 1918 Great Britain.

ROBERT A. OLEARY, Primary Examiner. M. A. ANTONA-KAS, AssistantExaminer.

1. A POWERED, DIRECT UPWARD DISCHARGE VENTILATOR FOR A BUILDINGCOMPRISING AND EXTRACTION FAN DUCT HAVING AN UPPER, UPWARDLY DIRECTEDOPEN END AND A LOWER OPEN END, SAID EXTRACTION FAN DUCT LEADINGEXTRACTED AIR FROM THE BUILDING ENTERING THE LOWER OPEN END OF THE DUCTFROM INSIDE THE BUILDING OUTSIDE THE BUILDING THROUGH THE UPPER UPWARDLYDIRECTED OPEN END OF THE DUCT, AND EXTRACTION FAN, FIRST MOUNTING MEANSMOUNTING SAID EXTRACTION FAN IN SAID EXTRACTION FAN DUCT, SECONDMOUNTING MEANS, ON SAID EXTRACTION FAN DUCT FOR MOUNTING THE DUCT TO THEBUILDING, NON-RETURN SHUTTERS MOUNTED ON THE UPPER UPWARDLY DIRECTEDOPEN END OF THE EXTRACTION FAN DUCT AND ARRANGED WHEN OPEN FOR THEDIRECT UPWARD DISCHARGE OF THE EXTRACTED AIR THROUGH THE UPPER UPWARDLYDIRECTED OPEN END OF THE EXTRACTION FAN DUCT, AND, WHEN CLOSED, TOWEATHER THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCTAND TO PREVENT DOWNDRAUGHT AND THE LOS OF HEAT FROM INSIDE THE BUILDING,A TUBULAR WINDSHIELD FOR SAID SHUTTERS, SAID WINDSHIELD HAVING A LOWEREND THRID MOUNTING MEANS ON SAID DUCT AND OUTSIDE SAID DUCT BELOW THELEVEL OF THE UPPER UPWARDLY DIRECTED OPEN END OF SAID DUCT AND MOUTINGSAID TUBULAR WINDSHIELD TO THE EXTRACTION FAN DUCT WITH THE LOWER END OFTHE WINDSHIELD BELOW THE LEVEL TO THE UPPER UPWARDLY DIRECTED OPEN ENDOF SAID EXTRACTION FAN DUCT, THE LOWER EDGE OF THE WINDSHIELDSURROUNDING THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FANDUCT WITH CLEARANCE AND DEFINING THEREWITH AN ANNULAR GAP, THEWINDSHIELD EXTENDING UPWARDLY ABOVE THE UPPER UPWARDLY DIRECTED OPEN ENDOF THE EXTRACTION FAN DUCT TO AN UPPER UPWARDLY DIRECTED OPEN ENDTHROUGH WHICH THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FANDUCT IS EXPOSED TO DIRECT WEATHER ENTRY, THE IMPROVEMENT CONSISTING INTHAT THE THIRD MOUNTING MEANS COMPRISES A PERIPHERAL OUTWARDLY DIRECTEDMOUNTING FLANGE ON THE EXTERIOR OF EXTRACTION FAN DUCT WHICH FLANGE ATLEAST SUBSTANTIALLY WHOLLY BLOCKS SAID ANNULAR GAP SO AS TO PREVENT THEENTRAINMENT OF AT LEAST ANY SUBSTANTIAL QUANTITY OF AIR FROM OUTSIDE THEBUILDING THROUGH THE LOWER END OF THE WINDSHIELD INTO THE AIRSTREAMDISCHARGING THROUGH THE UPPER, UPWARDLY DIRECTED END OF THE EXTRACTIONFAN DUCT, SAID EXTRACTION FAND DUCT COMPRISING A BASE PORTION HAVING ALOWER OPEN END DEFINING THE LOWER OPEN END OF THE DUCT, SAID BASEPORTION HAVING AN OUTWARDLY DIRECTED FLANGE AT ITS UPPER END, AND ANOPEN UPPER PORTION DEFINING THE UPWARDLY DIRECTED OPEN END OF THE DUCT,SAID UPPER PORTION HAVING AN OUTWARDLY DIRECTED FLANGE AT ITS LOWER ENDOVERLYING SAID FIRST SAID FLANGE AT THE UPPER END OF THE BASE PORTION OFTHE DUCT, THE OUTWARDLY DIRECTED FLANGE ON THE UPPER PORTION OF THE DUCTCONSTITUTING SAID PERIPHERAL MOUNTING FLANGE AND CARRYING SAIDWINDSHIELD, AND MEANS IS PROVIDED HINGEABLY CONNECTING SAID FLANGES.